1. Field of the Invention
The present invention relates to a high voltage device and method of fabricating the same, and more particularly to a lateral double diffused metal oxide semiconductor (LDMOS) transistor structure and method of fabricating the same.
2. Description of the Prior Art
High voltage devices are well known devices which form an integral part of modern day display panels, telecommunication systems, motor controllers, switch lock power supplies, inverters, and the like, by functioning as high voltage drivers. Due to the high voltage characteristics associated with these applications, the high voltage devices are required to have the capacity to withstand large supply voltages, sometimes in excess of 450 volts, without exhibiting breakdown.
Conventional high voltage devices include an isolator underneath the edge of the gate to improve the breakdown voltage of the device. Breakdown is believed to occur at the silicon surface underneath the gate edge when it has severe electric field crowding. The isolator can help to distribute the potential voltage drop; however, the on-resistance (Ron) is increased significantly by a deeper isolator because of the extra current path underneath the isolator. Ron is an important parameter, related to power loss. Low Ron is desirable for high voltage transistors.